isl_stream_read_map: properly read nested divs

[platform/upstream/isl.git] / isl_tab_pip.c

diff --git a/isl_tab_pip.c b/isl_tab_pip.c
index f9f700e..b63d3b7 100644 (file)
--- a/isl_tab_pip.c
+++ b/isl_tab_pip.c
@@ -10,6 +10,7 @@
  * ZAC des vignes, 4 rue Jacques Monod, 91893 Orsay, France 
  */
 
+#include <isl_ctx_private.h>
 #include "isl_map_private.h"
 #include <isl/seq.h>
 #include "isl_tab.h"
@@ -39,7 +40,7 @@
  * then the initial sample value may be chosen equal to zero.
  * However, we will not make this assumption.  Instead, we apply
  * the "big parameter" trick.  Any variable x is then not directly
- * used in the tableau, but instead it its represented by another
+ * used in the tableau, but instead it is represented by another
  * variable x' = M + x, where M is an arbitrarily large (positive)
  * value.  x' is therefore always non-negative, whatever the value of x.
  * Taking as initial sample value x' = 0 corresponds to x = -M,
@@ -2257,11 +2258,25 @@ static int context_lex_get_div(struct isl_context *context, struct isl_tab *tab,
        return get_div(tab, context, div);
 }
 
+/* Add a div specified by "div" to the context tableau and return
+ * 1 if the div is obviously non-negative.
+ * context_tab_add_div will always return 1, because all variables
+ * in a isl_context_lex tableau are non-negative.
+ * However, if we are using a big parameter in the context, then this only
+ * reflects the non-negativity of the variable used to _encode_ the
+ * div, i.e., div' = M + div, so we can't draw any conclusions.
+ */
 static int context_lex_add_div(struct isl_context *context, struct isl_vec *div)
 {
        struct isl_context_lex *clex = (struct isl_context_lex *)context;
-       return context_tab_add_div(clex->tab, div,
+       int nonneg;
+       nonneg = context_tab_add_div(clex->tab, div,
                                        context_lex_add_ineq_wrap, context);
+       if (nonneg < 0)
+               return -1;
+       if (clex->tab->M)
+               return 0;
+       return nonneg;
 }
 
 static int context_lex_detect_equalities(struct isl_context *context,
@@ -4251,7 +4266,7 @@ static __isl_give isl_map *basic_map_partial_lexopt(
  *
  *     a x >= -u >= -b_i(p)
  *
- * Moreover, m = min_i(b_i(p)) satisfied the constraints on u and can
+ * Moreover, m = min_i(b_i(p)) satisfies the constraints on u and can
  * therefore be plugged into the solution.
  */
 static __isl_give isl_map *basic_map_partial_lexopt_symm(